This program is concerned with ion transport processes operative in vascular smooth muscle and the role these processes play in altered vascular behavior during pathogenesis of hypertension. The specific areas related to hypertensive mechanisms are: (a) electrolyte exchange, (b) bioregulation, (c) calcium interactions and (d) small vascular changes. The areas to be investigated related to transport mechanisms in vascular and intestinal smooth muscle are: (a) phasic and tonic vessels, (b) interaction of passive and active transport, (c) isolated smooth muscle cells, (d) K influx kinetics and (e) calcium entry. The methods include: (1) isotope influx and washout techniques using K42 and Na24 Na22, Cl36, Ca45 and Co60 EDTA, (2) computer analyses of efflux kinetics, (3) ion analyses (Na, K, Ca, Mg, Sr, Cl) using atomic absorption spectroscopy, (4) chemical analyses (5) blood pressure with standard transducers, (6) muscle tension employing strain gauges.